1. Field of the Invention
This invention relates to an apparatus for cutting bone, and more particularly, to an apparatus for milling bone fragments which are subsequently demineralized and used to produce shaped materials.
2. Description of the Related Art
The use of demineralized bone fragments in the repair of bone defects and construction of shaped osteogenic materials such as sheets, plates, disks, pins, and the like has been known for some time. Shaped materials formed from pieces of demineralized bone and a method for forming such materials are disclosed in commonly assigned U.S. Pat. No. 5,298,254 to Prewett et al. The bone pieces utilized to form these shaped materials are preferably cut or machined to a desired size and dimension, with the geometry of the pieces being substantially regular in configuration.
A preferred method of machining or cutting bone fragments involves the use of a milling machine having a rotating cutter which produces substantially uniform bone fragments. Conventional prior art milling machines such as those disclosed, for example, in U.S. Pat. No. 4,242,019 to Roch, and U.S. Pat. No. 5,117,880 to Kapton et al. are not well suited for such a task however, since the working parts of these machines are not separated or isolated from the work area in which the bone fragments are produced. As a result, bone fragments produced from one piece of bone during a particular milling operation may become associated with the working parts of the machine, causing cross-contamination with bone fragments produced from another piece of bone in a subsequent milling operation.
It would be desirable therefore, to provide a milling machine in which the milling cutter and work area are isolated or separated from the working parts of the milling machine so that cross-contamination between differing work pieces can be prevented.